Multi-purpose compensator reduces muzzle climb, so you stay on target between shots during rapid fire engagements. Produces less concussion than most muzzle brakes for a smaller dust signature when shooting prone. California Legal Compensator is legal in all 50 states. BC1.0/1.5/2.0 fit .223/5.56 rifles with ½ x 28 tpi muzzle threads. BC1.5 is pre-drilled for permanent pinning to a 14.5" barrel to extend it to a civilian-legal 16.1" OAL. BC2.1 has the correct dimensions to accept add-on muzzle devices that fit over the standard A2 flash suppressor, including Gemtech HALO and AAC OMNI suppressors, and NOW INCLUDES the use of the Blank Firing Adapter (BFA) Groove for the New Gemtech Titanium HALO. BABC fits barrels chambered from 6.5 Grendel, 6.8 SPC, 7.62x39mm, .300 AAC Blackout, .308/7.62 NATO all the way to .300 WM. BC1.0/1.5/BA available with a matte stainless finish.